In Spudich and Fletcher (2008), henceforth SF, small start-time variations at each UPSAR station were erroneously omitted from the analysis, causing phase errors in the seismograms and affecting the strains and rotations inferred for the main shock and aftershocks. We present in this supplement the corrected figures not shown in the main text. We also present the corrected versions of the strain, rotation, and displacement gradient time series calculated for the main shock, which should be used in preference to the erroneous time series in the electronic supplement of SF.
Corrected figure 5. Calculated strains and rotations for the mainshock using stations 1 - 3 in the band 0.1 - 1.4 Hz. Row 1 is maximum shear strain across a vertical plane (solid) and total dilatation (dashed). Row 2 is torsion, row 3 is torsion rate, row 4 is tilt, row 5 is tilt rate, row 6 is the misfit ratio (which is essentially zero because the inversion is even-determined), and row 7 is the station P01 north component of velocity.
Corrected figure 6. Calculated strains and rotations for the mainshock using stations 1 - 3 in the band 0.1 - 3.6 Hz. Row 1 is maximum shear strain across a vertical plane (solid) and total dilatation (dashed). Row 2 is torsion, row 3 is torsion rate, row 4 is tilt, row 5 is tilt rate, row 6 is the station P01 north component of velocity.
Corrected figure 7. Calculated strains and rotations for the M4.7 2721724 event using stations 8 - 11 in the band 0.1 - 3.6 Hz. Row 1 is maximum shear strain across a vertical plane (solid) and total dilatation (dashed). Row 2 is torsion, row 3 is torsion rate, row 4 is tilt, row 5 is tilt rate, row 6 is the station P08 north component of velocity.
Corrected figure 8. Calculated strains and rotations for the mainshock using stations 8 - 11 in the band 0.1 - 1.4 Hz. Row 1 is maximum shear strain across a vertical plane (solid) and total dilatation (dashed). Row 2 is torsion, row 3 is torsion rate, row 4 is tilt, row 5 is tilt rate, and row 6 is the station P08 north component of velocity.
Corrected figure 9. Peak torsions of the four Parkfield events and their dependence on bandwidth. Measurements are from arrays 1-3 (gray), 8-11 (black), and 5-12 (asterisk). Squares are results for the 0.1 - 3.6 Hz band, crosses and asterisks are for the 0.1 -1.4 Hz band. An error in the symbols has also been corrected.
Corrected figure 10. Fourier amplitude spectra of velocity (solid) and scaled torsion (dashed) for the mainshock and the 2731710 aftershock as inferred on array 5-12 filtered with corners at 0.1 and 1.4 Hz. Velocity spectra are averages over all stations of the vector sum of the amplitude spectra of both horizontal components. Scaled torsions are torsions multiplied by 2.9 km/s, implying a phase velocity of 1.45 km/s.
Corrected figure 11. Fourier amplitude spectra of velocity (solid) and scaled torsion (dashed) for the mainshock (solid lines) and the 2731710 aftershock (dashed lines), as inferred on array 1-3 filtered with corners at 0.1 and 3.6 Hz. Velocity spectra are averages over all stations of the vector sum of the amplitude spectra of both horizontal components. Scaled torsions are torsions multiplied by 2 × 1.45 km/s. Amplitude spectra decay rapidly above 2 Hz, suggesting that most torsion power is found below 3.6 Hz.
We present in this section the strain, rotation, and displacement gradient time series calculated for the main shock. We present these time series for subarray 5-12 in the 0.1 - 1.4 Hz band, and for subarrays 1-3 and 8-11 in the 0.1 - 3.6 Hz bands.
spudich-fletcher-corrected-timeseries.zip. [1.0 MB]. Compressed zip archive containing three time series files. This file may be uncompressed on a Windows machine using PKUNZIP, WinZip, or other software. On a Mac this file can be uncompressed using StuffIt Expander or other software. On linux/unix the file may be uncompressed using the unzip command.
NOTE: These time series are band-limited. Their peak values do not agree with the broadband peak amplitudes listed in Table 3 of the Errata. Their peak amplitudes are slightly lower than the values in Table 2 of the Errata, owing to decimation to 50 samples / s. Peak amplitudes in that table are calculated using max(*) for dilatations and max(abs(*)) for all other quantities.
Contents of the zip file:
pkf_main_sub1-3_3.6hz_cor.txt - Main shock time series, subarray 1-3, 0.1 - 3.6 Hz pass band.
pkf_main_sub8-11_3.6hz_cor.txt - Main shock time series, subarray 8-11, 0.1 - 3.6 Hz pass band.
pkf_main_sub5-12_1.4hz_cor.txt - Main shock time series, subarray 5-12, 0.1 - 1.4 Hz pass band.
Files are ASCII.
Record 1: A title, identifying the earthquake, the subarray, and the pass-band.
Record 2: File version number, with time stamp of production date, in Pacific Daylight Time.
Record 3: Titles for each column.
Records 4 - end: Time series of 13 quantities, 1 quantity per column.
Column 1: Time (s) corresponding to each sample. Time is measured from the start of each time series. Time zero has no physical significance.
Column 2: Total dilatation (unitless). Corresponds to d in Appendix A.
Column 3: Horizontal dilatation (unitless). Corresponds to dh in Appendix A.
Column 4: Maximum total shear strain (unitless). Corresponds to s in Appendix A.
Column 5: Maximum horizontal shear strain (unitless). Corresponds to sh in Appendix A.
Column 6: Torsion (radians). Corresponds to w3 in Appendix A.
Column 7: Tilt (radians). Corresponds to sqrt(w12+w22) in Appendix A.
Column 8: Displacement gradient (unitless). Corresponds to p1 in Appendix A.
Column 9: Displacement gradient (unitless). Corresponds to p2 in Appendix A.
Column 10: Displacement gradient (unitless). Corresponds to p3 in Appendix A.
Column 11: Displacement gradient (unitless). Corresponds to p4 in Appendix A.
Column 12: Displacement gradient (unitless). Corresponds to p5 in Appendix A.
Column 13: Displacement gradient (unitless). Corresponds to p6 in Appendix A.
